1. Field of the Invention
The present invention relates to an indicated position recognizing apparatus and an information input apparatus having the same.
2. Description of the Related Art
Conventional systems have developed handwriting information input systems where characters, image information, and so on are written on a screen using an input pen. The handwritten information is digitized, and the information is displayed on the screen, and various apparatuses have been proposed.
A writing pen apparatus proposed in Japanese Patent Laid-Open No. 8-36452 (Patent Document 1) includes a writing pen and a sheet of writing paper. The sheet has a pattern such that the sheet's reflecting characteristic varies. The writing pen detects the difference in the reflecting characteristic of the pattern on the sheet, thereby detecting the motion of the writing pen and the coordinate.
In a handwritten information input system proposed in Japanese Patent Laid-Open No. 2001-56749 (Patent Document 2), two predetermined floodlight units form, by projecting light beams, a coordinate-indicating area, where the coordinate-indicating area is substantially the same as an information-displaying surface of the recording medium. On the basis of the distance between the floodlight units, the optical output values of the light beams emitted from the light sources are changed. In this way, the positional information of a locus, handwritten using a writing device on the information-displaying surface of the recording medium, can be detected regardless of the size of the recording medium.
There have been proposed various optical scanning apparatuses such that a light beam emitted from a light source device forms a spot on a surface to be scanned, a scanning device two-dimensionally scans the light beam on the surface to be scanned, and a two-dimensional image is formed by the afterimage effect (Japanese Patent Laid-Open Nos. 2001-281583 and 11-84291 (Patent Documents 3 and 4)).
In the writing pen apparatus described in Patent Document 1, it is necessary to set a pattern such that the reflecting characteristic is gradually changed, on a sheet of writing paper, and it is necessary to always carry the sheet of writing paper.
In the handwritten information input system described in Patent Document 2, it is necessary to highly accurately dispose the two floodlight units with respect to the coordinate of the writing area.
The apparatuses of Patent Documents 1 and 2 are apparatuses for obtaining the information handwritten on paper, and do not project and display an image on a predetermined surface for themselves.